The invention relates to a gas-pedal module having a gas pedal which is mounted in a housing and can be actuated, counter to the force of a restoring spring, with pedal-force-dependent hysteresis, and having a pedal-position sensor which produces an electric signal corresponding to the pedal position.
In gas pedals for motor vehicles, use is being made increasingly frequently of so-called "drive-by-wire" systems, in the case of which the gas pedal is no longer connected to the throttle via a Bowden wire, as has been the case up until now, but rather a sensor produces an electric output signal which corresponds to the gas-pedal position and passes, via lines, to an engine control system, which activates the throttle via an electric actuating motor in dependence on the signals.
From the Bowden wires which have usually been used up until now, the vehicle drivers are accustomed, during actuation of the gas pedal, to a force hysteresis which is derived from the frictional forces acting in the Bowden wire. These frictional forces set an increased resistance against the pressing-down action of the pedal and, when a certain gas-pedal position is being held, relieve the driver's foot of the restoring forces of the restoring spring. The counter pressure, when the gas pedal is pressed down, allows more precise positioning of the gas pedal, while the foot being relieved when a gas-pedal position is being held improves comfort.
With the "drive-by-wire" systems, attempts were made to maintain these desirable characteristics of the gas pedal, for which purpose a simulation of the properties of a Bowden wire with its restoring spring was necessary.
In order to simulate the hysteresis, use is usually made of direction-dependent frictional elements, as are outlined, for example, in DE 195 17 172. This document also discloses the conventional play-free mounting of the gas pedal in a housing. Since the mounting of the gas-pedal lever, on the one hand, has to be precise but also, at the same time, has to absorb very high pedal forces, a particularly high-quality, play-free mounting (for example needle bearings) has to be provided in order to avoid the possible occurrence of jamming. The costs of such a gas-pedal module are thus considerable.